http://edition.cnn.com/2005/HEALTH/conditions/11/16/pdg.gender.selection/index.html

 

 

 

A sample of sperm was spun in a centrifuge. The spinning separates the Y sperm that creates a boy from the X sperm that creates a girl. The Y sperm was used to fertilize Beth's egg.

 

 

SO .. which sperm will have a lower mass ???

The one with X or Y

SO .. which sperm will have a lower mass ???

The one with X or Y

The one with Y. The Y chromasome is much smaller than the X chromasome.

I believe they also did this with a magnetic field... not sure how though.

here are two methods explained using pictures

 

http://www.washingtonpost.com/wp-srv/nation/daily/graphics/sexselection_121404.html

 

one uses a dye (that stains chromosomes)

a laser (the XX is bigger so it glows more)

a mild static electric charge applied to the desired type of sperm

passage between charged plates to get a stream of the desired type

 

the other method uses in vitro where you let them grow until they have 8 cells or so and then examine one cell to see what the gender is

 

I know there are other methods too, like centrifuge, but only have this link that explains these two methods

http://www.in-gender.com/cs/blogs/gender_selection_news/archive/2006/1/13/5342.aspx

 

There's no dispute that the X chromosome is bigger than the Y chromosome. But the sex chromosome is only one of the 23 chromosomes carried by a sperm -- in total, an X sperm carries only 2.9% more genetic material than a Y sperm. As you can see, the difference isn't that great.

Great enough to seperate them.